Bottom Line:
This is especially true in the area of nanomedicine, due to physicochemical properties, such as mechanical, chemical, magnetic, optical, and electrical properties, compared with bulk materials.The first goal of this study was to produce silver nanoparticles (AgNPs) using two different biological resources as reducing agents, Bacillus tequilensis and Calocybe indica.Cells pretreated with pifithrin-alpha were protected from p53-mediated AgNPs-induced toxicity.

Background: Recently, the use of nanotechnology has been expanding very rapidly in diverse areas of research, such as consumer products, energy, materials, and medicine. This is especially true in the area of nanomedicine, due to physicochemical properties, such as mechanical, chemical, magnetic, optical, and electrical properties, compared with bulk materials. The first goal of this study was to produce silver nanoparticles (AgNPs) using two different biological resources as reducing agents, Bacillus tequilensis and Calocybe indica. The second goal was to investigate the apoptotic potential of the as-prepared AgNPs in breast cancer cells. The final goal was to investigate the role of p53 in the cellular response elicited by AgNPs.

Methods: The synthesis and characterization of AgNPs were assessed by various analytical techniques, including ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The apoptotic efficiency of AgNPs was confirmed using a series of assays, including cell viability, leakage of lactate dehydrogenase (LDH), production of reactive oxygen species (ROS), DNA fragmentation, mitochondrial membrane potential, and Western blot.

Results: The absorption spectrum of the yellow AgNPs showed the presence of nanoparticles. XRD and FTIR spectroscopy results confirmed the crystal structure and biomolecules involved in the synthesis of AgNPs. The AgNPs derived from bacteria and fungi showed distinguishable shapes, with an average size of 20 nm. Cell viability assays suggested a dose-dependent toxic effect of AgNPs, which was confirmed by leakage of LDH, activation of ROS, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells in MDA-MB-231 breast cancer cells. Western blot analyses revealed that AgNPs induce cellular apoptosis via activation of p53, p-Erk1/2, and caspase-3 signaling, and downregulation of Bcl-2. Cells pretreated with pifithrin-alpha were protected from p53-mediated AgNPs-induced toxicity.

Conclusion: We have demonstrated a simple approach for the synthesis of AgNPs using the novel strains B. tequilensis and C. indica, as well as their mechanism of cell death in a p53-dependent manner in MDA-MB-231 human breast cancer cells. The present findings could provide insight for the future development of a suitable anticancer drug, which may lead to the development of novel nanotherapeutic molecules for the treatment of cancers.

Mentions:
Powers et al48 proposed dynamic light scattering (DLS) as a useful technique for evaluating particle size and size distribution of nanomaterials in solution. To determine particle size in aqueous or physiological solutions, DLS analysis was performed.48 The characterization of nanoparticles in solution is essential before assessing in vitro toxicity.49 Particle size, size distribution, particle morphology, particle composition, surface area, surface chemistry, and particle reactivity in solution are important factors in assessing nanoparticle toxicity.49 In the present study, DLS was used to evaluate the size distribution of B-AgNPs and F-AgNPs. The B-AgNPs and F-AgNPs showed an average size of 20 nm, which is consistent with that observed by TEM (Figure 4). Further, we evaluated the size distribution in DMEM media and DMEM media with 10% FBS. The results depicted that the average size of B-AgNPs was 20±2.0, 60±10.0, and 30±5.0 nm in water, DMEM media, and DMEM with 10% FBS, respectively. The average size of F-AgNPs was 20±5.0, 70±10.0, and 35±10.0 nm in water, DMEM media, and DMEM with 10% FBS, respectively (Figure 4). The results show that AgNPs in the presence of DMEM media and DMEM media with 10% FBS exhibited larger size than the AgNPs dispersed in water. However, DMEM media with 10% FBS showed slight variation in AgNP sizes. Murdock et al49 observed that polysaccharide-coated AgNPs showed an increase in the size from 80 to 250 nm and 1,230 nm in water and media with serum, respectively. Han et al26 also observed that the AgNPs dispersed in media were larger in size than those dispersed in water.

Mentions:
Powers et al48 proposed dynamic light scattering (DLS) as a useful technique for evaluating particle size and size distribution of nanomaterials in solution. To determine particle size in aqueous or physiological solutions, DLS analysis was performed.48 The characterization of nanoparticles in solution is essential before assessing in vitro toxicity.49 Particle size, size distribution, particle morphology, particle composition, surface area, surface chemistry, and particle reactivity in solution are important factors in assessing nanoparticle toxicity.49 In the present study, DLS was used to evaluate the size distribution of B-AgNPs and F-AgNPs. The B-AgNPs and F-AgNPs showed an average size of 20 nm, which is consistent with that observed by TEM (Figure 4). Further, we evaluated the size distribution in DMEM media and DMEM media with 10% FBS. The results depicted that the average size of B-AgNPs was 20±2.0, 60±10.0, and 30±5.0 nm in water, DMEM media, and DMEM with 10% FBS, respectively. The average size of F-AgNPs was 20±5.0, 70±10.0, and 35±10.0 nm in water, DMEM media, and DMEM with 10% FBS, respectively (Figure 4). The results show that AgNPs in the presence of DMEM media and DMEM media with 10% FBS exhibited larger size than the AgNPs dispersed in water. However, DMEM media with 10% FBS showed slight variation in AgNP sizes. Murdock et al49 observed that polysaccharide-coated AgNPs showed an increase in the size from 80 to 250 nm and 1,230 nm in water and media with serum, respectively. Han et al26 also observed that the AgNPs dispersed in media were larger in size than those dispersed in water.

Bottom Line:
This is especially true in the area of nanomedicine, due to physicochemical properties, such as mechanical, chemical, magnetic, optical, and electrical properties, compared with bulk materials.The first goal of this study was to produce silver nanoparticles (AgNPs) using two different biological resources as reducing agents, Bacillus tequilensis and Calocybe indica.Cells pretreated with pifithrin-alpha were protected from p53-mediated AgNPs-induced toxicity.

Background: Recently, the use of nanotechnology has been expanding very rapidly in diverse areas of research, such as consumer products, energy, materials, and medicine. This is especially true in the area of nanomedicine, due to physicochemical properties, such as mechanical, chemical, magnetic, optical, and electrical properties, compared with bulk materials. The first goal of this study was to produce silver nanoparticles (AgNPs) using two different biological resources as reducing agents, Bacillus tequilensis and Calocybe indica. The second goal was to investigate the apoptotic potential of the as-prepared AgNPs in breast cancer cells. The final goal was to investigate the role of p53 in the cellular response elicited by AgNPs.

Methods: The synthesis and characterization of AgNPs were assessed by various analytical techniques, including ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The apoptotic efficiency of AgNPs was confirmed using a series of assays, including cell viability, leakage of lactate dehydrogenase (LDH), production of reactive oxygen species (ROS), DNA fragmentation, mitochondrial membrane potential, and Western blot.

Results: The absorption spectrum of the yellow AgNPs showed the presence of nanoparticles. XRD and FTIR spectroscopy results confirmed the crystal structure and biomolecules involved in the synthesis of AgNPs. The AgNPs derived from bacteria and fungi showed distinguishable shapes, with an average size of 20 nm. Cell viability assays suggested a dose-dependent toxic effect of AgNPs, which was confirmed by leakage of LDH, activation of ROS, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells in MDA-MB-231 breast cancer cells. Western blot analyses revealed that AgNPs induce cellular apoptosis via activation of p53, p-Erk1/2, and caspase-3 signaling, and downregulation of Bcl-2. Cells pretreated with pifithrin-alpha were protected from p53-mediated AgNPs-induced toxicity.

Conclusion: We have demonstrated a simple approach for the synthesis of AgNPs using the novel strains B. tequilensis and C. indica, as well as their mechanism of cell death in a p53-dependent manner in MDA-MB-231 human breast cancer cells. The present findings could provide insight for the future development of a suitable anticancer drug, which may lead to the development of novel nanotherapeutic molecules for the treatment of cancers.